This invention relates generally to devices capable of determining fall velocities of hydrometeors, and, more particularly, to a fall velocity indicator/viewer which is extremely reliable in determining the velocity of naturally falling snowflakes as well as providing a clear observation area for viewing the naturally falling snowflakes.
It has long been recognized that electro-optical and communication systems are especially susceptible to attenuation because of falling snow. In addition to falling snow, other types of hydrometeors or particulate matter can have an adverse affect on electro-optical and microwave systems as well as other communication systems. Therefore, it becomes extremely important to document not only the velocity of such naturally falling hydrometers such as snowflakes, but also to observe, at close range, the snowflake itself. By analyzing information based upon the oscillation of snowflakes, the conditions at which they tumble, the specific type of crystals that transverse a point along a line of sight, and the relationship between fall speed and particle size, steps may then be taken to lessen the attenuation effects caused by naturally falling hydrometeors such as snowflakes. In addition, it is essential that the above observations and determinations be made with "naturally falling" hydrometeors, and not be limited to only snowflakes but also include other hydrometeors such as rain, drizzle, hail, graupel and freezing rain.
Heretofore, devices utilized in determining the velocity of falling objects were lacking in many of the areas recited above. Consequently, it is becoming increasingly essential to develop a device which not only is able to accurately and reliably determine fall rate velocity, but is also capable of providing a clear and accurate observation area in order to study the hydrometeors under naturally occuring conditions.